<template>
  <div>
    <!-- 头部部分 -->
    <header class="header">
      <h1>todos</h1>
      <input 
      class="new-todo" 
      placeholder="请输入任务名称" autofocus  
      @keyup.enter="headerContent" 
      v-model.trim="todoName"
      />
    </header>
  </div>
</template>

<script>
export default {
  name: 'ListHeader',
  props: {},
  data() {
    return {
      todoName:''
    }
  },
  methods: {
    headerContent(){
      // 判断非空
      if(this.todoName === '') return alert('输入的内容不能为空')

      this.$emit('headerContent',this.todoName)

      // 输入过后内容清空
      this.todoName = ''
    }
  },
}
</script>

<style scoped></style>
